BOULDER, Colo. (CBS4) – A private music instructor from Boulder has been accused of sexually assaulting one of his students.

The Boulder County Sheriff’s Department says Brian Douglas Trumble, 51, turned himself in Thursday. Investigators say the alleged victim is a 15-year-old girl who took lessons from Trumble for 6 years.

Trumble also works as a substitute teacher for the Boulder Valley School District. A spokesman says they do not believe any inappropriate behavior happened at a school.